The overall objective of this project is to determine any in vivo effect on the incidence of recurrent colon carcinomas by immunization of animals at risk using a variety of cell surface antigens already shown to be associated with dimethylhydrazine ((DMH)-induced rat colon carcinomas. After primary DMH-induced tumors are "curatively" resected, animals will be treated with either irradiated autochthonous tumor, "tissue-type specific" syngeneic colon tumor, or rat colon cancer-related embryonic tissue. Individual animals will be followed by serial double contrast studies of their large bowel until a majority of control-treated animals develop suture line recurrences or second colon primaries. Host immune parameters will be followed serially using in vitro assays for cell-mediated cytotoxicity, complement-dependent cytotoxicity, and changes in nonspecific circulating immune complexes. These serial in vitro parameters of host immune response will be followed during DMH treatment and until primary tumor development, after "adjuvant" immunization following primary tumor resection, and until the development of subsequent tumor recurrences.